Problem: Solve for $z$ : $25 = z + 23$
Subtract $23$ from both sides: $ \begin{eqnarray} \\ \hphantom{25 {- 23}} &\hphantom{=}& \hphantom{z} \\ 25 &=& z + 23 \\ \\ {-23} && {-23} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ 25 {- 23} &=& z \\ \end{eqnarray} $ Simplify. $ z = 2$